[435competition]

Hey guys,

I have a 14 N55 435i and while tuning it, mid tune the computer died and left my fuel pump running. It was running for a good 5-7 minutes until I was able to get it off. I then proceed to start the car and the cold start was significantly louder. Probably since there’s more fuel from the fuel pump running so much. Now I drove it for less than a mile and it’s been fine. After a bit, just getting on the throttle it suddenly feels like the car was doing anti-lag. It’s not in the tune but just saying it sounds like it. Then I let off. A few moments after it did it all the time and the car now feels like it’s stuttering. Misfiring etc. no codes came up on the tune. After that I flashed it back to stock and I get drive train malf. Codes read back cyl 4 misfire. The car only has 30k mi. Could this be a bad injector or something else. What could’ve the fuel pump running for so long caused any other damage? Hpfp? Any thoughts and prior experience please let me know.

Thx!

[BashShah]

ok the car is saying cyl 4 miss fires.
I would move the Coil to cyl1. and Plug to Cyl 2.

see if the fault follows.
this the first step.....rule it out.

What diagnostic scanner did you use?

[435competition]

Originally Posted by BashShah

ok the car is saying cyl 4 miss fires.
I would move the Coil to cyl1. and Plug to Cyl 2.

see if the fault follows.
this the first step.....rule it out.

What diagnostic scanner did you use?

I used Ista, since then I swapped both plugs and coils from 4 to 3 and the misfire changed from 4 to 3. It’s looking good. I have spare coils that are fs good. Gotta order a new set of spark plugs. Will update when that’s sorted! Thx

[BashShah]

Glad you are almost done, but I still say that you should now, move ONLY the Coil to 1.
and Plug to 2, and see which is the actual culprit.

If it is the Plug, then replace all 6.
and be worry free for a long time.

[435competition]

Just replaced the plugs since I have fcp euro lifetime warranty. Issue still persists. I had some spare 17k mi ignition coils laying around so swapped that out with cylinder 3 and 4 ignition coil and success! No more misfire. What could’ve caused a new Delphi ignition coil to go bad?